We propose to study the social transmission of (a) alcohol, tobacco and other drug use (ATOD), and (b) health-risking sexual behavior (HRSB) across three generations (G1, G2, and G3).The developmental pathways of precursors (e.g., ATOD awareness) and of the emergence of these behaviors will be examined from ages 22 months to 17-18 years. A dynamic developmental systems approach will be used to examine prospectively the transmission of contextual risk and problematic behaviors across three generations, and parenting behaviors and peer influences across two generations. Hypotheses will be tested on a community sample consisting of the children of at-risk early adult men (G2) in the Oregon Youth Study (OYS). Up to two biological children of the fathers per mother are included in the Three Generational Study (3GS). The OYS men show high levels of antisocial behavior (at age 25 years, 42% had 2 or more arrests) and substance use (estimated 50% lifetime diagnoses for alcohol dependence or abuse). The men are currently ages 30-32 years, and with their parents (G1) have been involved in the OYS since the G2 men were ages 9-10 years. Both general pathways of risk via early developmental processes and common pathway psychopathology as well as specific influences, including peer social influences and family deviant contexts, will be examined. Child risk factors examined will include temperament. We expect that initiation of substance use will be predicted by factors related to the development of conduct problems and by the specific effects of exposure to substance use by parents in childhood and by peers in later childhood. The design also allows for a genetically-informed examination of cross-generational transmission as pairs of biological siblings are included in the study. Hypotheses regarding cross-generational congruence in the shapes of growth patterns across key developmental periods will be examined. We plan to address the Specific Aims by a combination of secondary data analysis of the OYS, OYS-Couples, and 3GS extant data sets, which will be undertaken from the beginning of the proposed study period, and by collecting and analyzing data that will: (a) Expand the sample size for the early time points (1 through 6, ages 22 months to 11 years), and (b) Extend the study to age 17-18 years.